Laser treatment of benign prostatic hypertrophy

ABSTRACT

The method of treating benign prostatic hyperplasia comprises trans-perineally introducing at least one energy delivery device through a perineal area of the patient in a first position in a prostate of the patient. Once the energy delivery device has been introduced, energy is delivered through the delivery device to a volume of tissue of the prostate, until the volume is vaporized or sublimated and a cavity is formed in the prostate tissue. The energy delivery device can then be removed from the prostate. Vaporization of adenomatous tissue provides immediate relieve of the urethra compression.

TECHNICAL FIELD

Disclosed herein are ablative treatments of human or animal body.Embodiments disclosed herein specifically concern the treatment ofBenign Prostatic Hyperplasia or Benign Prostatic Hypertrophy (shortlyhere on referred to also as BPH) by ablation therapy. Some embodimentsspecifically refer to laser ablation therapy.

CLINICAL BACKGROUND

Benign Prostatic Hyperplasia (BPH), also known as Benign ProstaticHypertrophy, is a benign pathology of the prostate characterized byproliferation of prostate cellular elements. Cellular accumulation andgland enlargement may result from both epithelial and stromalproliferation and/or reduced cell death (apoptosis). The enlarged glandhas been proposed to contribute to the overall lower urinary tractsymptoms (LUTS).

BPH/LUTS prevalence rates ranges from 50% to 75% among men 50 years ofage and older to 80% among men 70 years of age and older. The overallincidence rates ranges from 8.5 to 41 cases/1000 person per years.

The presence of moderate-to-severe LUTS was also associated with thedevelopment of acute urinary retention (AUR) as a symptom of BPHprogression, increasing from a prevalence of 6.8 episodes per 1000patient years of follow-up in the overall population to a high of 34.7episodes in men aged 70 and older with moderate to severe LUTS.

Enlargement of the prostate involves a series of compression symptomsthat also affect the dynamics of urination and greatly alter the qualityof life of the affected patient. Although LUTS secondary to BPH(LUTS/BPH) is not often a life-threatening condition, the impact ofLUTS/BPH on quality of life (QoL) can be significant and should not beunderestimated. Some symptoms include: hesitation, weak and/orintermittent urinary stream, urinary retention, burning sensation and/orpain during urination, dysuria, urgency incontinence (urgent need tourinate), urination frequency, urine leakage, incontinence, dribbling atthe end of urination, nocturia, incomplete emptying of the bladder,straining.

TURP (transurethral resection of prostate) is today the most commontechnique in the treatment of BPH. This technique represents anevolution of open surgery achieving improvement in LUTS symptoms withlower hospitalization time. The technique, which nowadays represents thegold standard, consists in the removal of the enlarged tissue by meansof a surgical instrument called a resectoscope inserted into the penisthrough the urethra, such that no external incision is required, asinstead in the case of open surgery. In this way, the hypertrophictissues of the prostatic gland, which creates compression on theurethra, is sliced in small pieces and removed by the resectoscope. TURPis performed in general anesthesia or spinal anesthesia and requiresfrom one to two hospital recovery after the procedure. A catheter isneeded due to swelling that blocks urine flow in post treatment(generally left in place for at least 24 to 48 hours).

TURP is still considered an aggressive surgery involving several acuteand chronic complications that can greatly affect the life of thepatient in post-surgery. Bleeding especially in patients receiving ananticoagulant therapy (heparin, coumadin related compounds, antiplateletagents) remains a concern and may require, although rarely, bloodtransfusion.

Additional several post-treatment urinary symptoms exist, due to thefact that the urethra epithelium has been completely removed. Forinstance urination may be painful; a sense of urgency or frequenturination 6 to 8 weeks after TURP has also been reported by patients.One of the possible permanent side effects of TURP is retrogradeejaculation which results when the tiny sphincter muscle that usuallyblocks off the bladder during ejaculation is damaged during theprocedure. This side effect can force patient to sterility. The maincomplications of TURP and their incidence are:

-   -   temporary difficulty urinating (urinary retention): 3%    -   urinary tract infection: 1.7%    -   erectile dysfunction: 2.1-11%    -   heavy bleeding: transfusion rate 0.4%    -   difficulty holding urine (early urge incontinence): 30-40%    -   need for retreatment due to urethral strictures (2.2-9.8%)    -   bladder neck contractures (0.3-9.2%)

In order to improve the patient's quality of life, a number ofmini-invasive techniques have been developed to achieve symptomaticremission with reduced hospitalization time and less complication rates.Based on the different approaches on which they are based, thesetechniques can be grouped as follows:

A. Techniques aimed at immediately removing an excess hypertrophictissue (as TURP but with less complications and side effects). In thissense, PVP (Photo Selective Vaporization, HoLAP Holmium Laser Ablation,HoLRP holmium laser resection, HoLEP-TuLEP Holmium Laser Enucleation,Thulium Laser Enucleation) have been developed. All of these techniquesare performed by a trans-urethral approach using a cystoscope andinclude the use of power laser that is brought into the working area bycontact or non-contact optical fibers to vaporize or resect hypertrophictissue. Among techniques of this first group, the following can bementioned:

-   -   a. Visual Laser Ablation of the Prostate (VLAP): This procedure        is performed by trans-urethral approach and consists of lasing        prostatic tissue in a noncontact fashion to create an area of        heat-induced coagulative necrosis that extends about 10 mm into        the tissue. Edema and prolonged sloughing of the coagulated        tissue leads to irritation at the level of the lower urinary        tract and to urinary retention requiring long periods of        catheterization, up to 3 months, in up to 30% of cases;    -   b. Photo Selective Vaporization (PVP): According to this        technique, the urethral and periurethral tissue that causes        obstruction is vaporized with the purpose of reopening the        urinary duct immediately. A KTP laser (wavelength of 532 nm,        visible green light) with a side firing fiber in a non-contact        mode is used for this application. This wavelength is strongly        absorbed by hemoglobin and therefore has a very short absorption        depth in well-vascularized tissue such as the prostate;    -   c. Holmium Laser Ablation (HoLAP): An Holmium laser is used to        produce vaporization of the tissue;    -   d. Holmium Laser Resection of Prostate (HoLRP): This technique        expects to use high-density laser energy to vaporize/incising        exceeding tissue which is cut into small pieces that fall into        the bladder and are then subsequently expelled;    -   e. Holmium-Thulium Laser Enucleation (HoLEP-TuLEP): Resection of        the entire hypertrophic lobe is achieved through a contact        optical fiber that vaporizes and separates tissues. The large        removed lobes fall into the bladder and are removed by        morcellation, which takes considerable time especially for big        prostates;    -   f. Trans-Urethral Incision of the Prostate (TUIP): a contact        optical fiber and a high energy laser are used to produce an        incision in the periurethral tissue that behaves as an        alternative urine channel,        B. Techniques aimed at preserving the prostatic urethra and its        urothelium. These techniques usually exploit a minimally        invasive approach and consist of placing an energy applicator        directly into the prostatic adenoma by a cystoscope.        Radiofrequency, microwave, or laser energy are released into the        adenoma and, due to tissue absorption mechanisms, are        transformed into heat with increasing local temperature.        Temperature and exposure time induce irreversible cell damage        and coagulation of small vessels with subsequent cell death in        the surrounding tissue. Necrotic tissue is subsequently        reabsorbed by the physiological wound healing mechanism of the        human body and a prostatic volume reduction takes place, with        consequent remission of BPH symptoms. There is also the        possibility of obtaining necrosis of the tissues by the use of        cryoablation, applied to the hypertrophic area resulting from        several freezing-unfreezing cycles. Thermal energy techniques        are reported below:    -   a) The radiofrequency technique has been named Transurethral        Needle Ablation (TUNA). It involves positioning electric needles        through the urethra in the hypertrophic part and generating        alternating electric current between the needle tips and a        recovery plate placed on the patient's skin (usually behind the        legs). The current heats the prostatic tissue by Joule effect        and determines cell death due to increased temperature. Urethra        burns and consequent damages may occur due to incorrect needle        positioning and to poor flow control of the current circulating        in low impedance paths. These effects are unpredictable and thus        unavoidable;    -   b) The procedure using microwaves on the prostate is called        Transurethral Microwave Therapy (TUMT) and consists of a        catheter with an antenna that is placed in the urethra through a        blistered bladder balloon. The portion of the urethral tissue        facing the antenna undergoes the highest temperatures of the        generated thermal field and this usually causes irreversible        necrosis of the urethral and surrounding tissues;    -   c) The technique using laser radiation to obtain tissue        coagulation goes under the name of Interstitial Laser        Coagulation (ILC). The procedure is performed by placing        laser-diffusing fibers directly into the prostatic adenoma,        either via the transurethral cystoscopic approach, or the        perineal approach. The ILC laser technique uses particular        optical diffusers to avoid overheating the tissues close to the        tip of the flat type fiber optic. These fiber tip diffusers        allow treating extended tissue portions by maintaining optical        density at levels such as to induce tissue coagulation, with        temperatures below 100° C. Some systems have a temperature        feedback control to maintain the temperature within the desired        range of 80−100° C. (Indigo® Optima Laser Treatment System;        Ethicon Endo-Surgery, Cincinnati, Ohio). Optical diffusers        generally have a higher caliper than bare optical fibers,        because they are equipped with a protective optically        transparent dome. The procedure induces substantial tissue edema        and hence necessitates prolonged (7-21 days) postoperative        catheterization. Retreatment rates are problematic: as high as        20% at 2 years, 41% at 3 years and 50% at 54 months.

Summarizing, trans-urethral laser techniques involving vaporization orvapor-enucleation of the exceeding tissue causes destruction of theurethral portion and it takes several weeks for new epithelization andwound healing. This type of approach implies much of the side effectsand complications of treatment such as prolonged bleeding, difficultyurinating, burning, infections.

Techniques that produce tissue coagulation by a transurethral (with acystoscope) or trans-perineal (under the ultrasound transcriptionalguide) approach are aimed at preserving the functional anatomicalstructures of the gland and induce a coagulative necrosis in the centralpart of the adenoma. Anyway, the transurethral approach maintains arelative high risk of urethra damage and transperineal approach ispreferred as safer and prone to less complications. However, the maindrawback remains the slow improvement of symptoms which takes severalweeks or months to take place.

A need therefore exists, for more efficient, less invasive treatments ofBPH, which also may result in faster recovery and less post-operativediscomfort for the patient.

SUMMARY

Disclosed herein is a method for treating benign prostatic hypertrophyby tissue removal, which exploits the advantages of the trans-perinealapproach and energy-tissue interaction in order to remove enlargedtissues of the adenoma leaving intact all the critical prostatic andperi-prostatic structures, such as gland capsule, urethra, neurovascularbundles. Enlarged tissue removal by local energy application leads tothe formation of cavities with an immediate reduction of glandcompression on adjacent structures and urethra followed by the remissionof LUTS symptoms.

According to one aspect, the subject matter disclosed herein concerns amethod of treating benign prostatic hyperplasia in a patient in need ofsaid treatment, comprising the following steps:

-   -   trans-perineally introducing at least one energy delivery device        through a perineal area of the patient in a first position in a        prostate of the patient;    -   delivering energy from an energy source through the energy        delivery device to a first volume of tissue of said prostate,        until said first volume is vaporized or sublimated and a cavity        is formed in the prostate tissue;    -   removing the energy delivery device from the prostate; and    -   reducing the volume of the cavity such that compression of the        urethra by prostate tissue surrounding the urethra is relieved.

While several embodiments disclosed here on use laser energy, the optionof using other sources of energy is not excluded. Laser beam can beeasily conveyed through optical fibers, which may be beneficial sinceless invasive treatments are possible.

Optical fibers with very a small diameter can be introduced in theadenomatous tissue with very fine needles or introducers in order todeliver laser energy. The number of treatment sites (i.e. cavityformation by removal of hypertrophic tissue) can be arbitrary chosen.One, two or more needles and relevant fibers can be introduced inseveral positions of the prostate, to perform simultaneous treatment indifferent volumes of the prostate. In some embodiments, needles can bearranged symmetrically with respect to a sagittal plane.

In some embodiments, one optical fiber is introduced through each needleor introducer. Each optical fiber can be coupled to a respective energysource, in particular a respective laser source. Thus, in someembodiments, a number of laser sources equal to the number of needlesand optical fibers simultaneously introduced in the prostate formultiple simultaneous treatments can be used. This renders the treatmentfaster and reduces patient's discomfort.

The energy delivered in the prostatic tissue is modulated to provokevaporization of water contained in the tissues. The energy can alsointeract with carbon or other substances contained in the tissues andprovoke sublimation thereof. Measures can be taken to remove gaseousmaterial resulting from the energy/tissue interaction. As understoodherein, gaseous material can include gases or vapors resulting fromvaporization or sublimation of tissue.

The vaporization and possible sublimation generate cavities in thetissue, which can result in immediate reduction of the bulk of thegland, and therefore immediate relieve of the compression provoked byswollen adenomatous tissue on the urethra. The more the tissue removal,the more effective the treatment is. Single cavities generated byseveral energy applicators, such as optical fibers, can also merge in alarger cavity, depending on the distance between the tips of the opticalfibers used during treatment and treatment parameters.

The trans-perineal approach is less traumatic than trans-urethral ortrans-rectum approach and allows a lower risk of infections and isperformed under local anesthesia, or even without anesthesia, if thinneedles are used. As a consequence, the described treatment can becarried out in outpatient setup without general or spinal anesthesiawith very short recovery times for the patient and less or nohospitalization costs. Moreover, as critical prostate structures arepreserved, in particular the urethral lumen, catheterization can bereduced or avoided.

Presently preferred embodiments involve the use of optical fibers whichare introduced through thin needles that are inserted into the glandunder image monitoring (ultrasound or magnetic resonance imaging).Optical fibers may have a core diameter preferably ranging from 100 to500 micrometers. Thin optical fibers can be introduced through very thinneedles, e.g. 25 G-20 G caliper needles, which can be used without localanesthesia.

According to a further aspect, disclosed herein is a method of removingtissue form an organ of a patient, comprising the following steps:

introducing at least one energy delivery device in a first position inan organ of the patient;

delivering energy from an energy source through the energy deliverydevice to a first volume of tissue of said organ, until said firstvolume is vaporized or sublimated and a cavity is formed in the organtissue;

removing the energy delivery device from the organ.

Several further features and embodiments of the methods disclosed hereinare described in more detail here on and are set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosed embodiments of theinvention and many of the attendant advantages thereof will be readilyobtained as the same becomes better understood by reference to thefollowing detailed description when considered in connection with theaccompanying drawings, wherein:

FIG. 1 illustrates a schematic cross-sectional view of a prostateaffected by BPH;

FIG. 2 illustrates another schematic cross-sectional view, according toa sagittal plane, of a prostate affected by BPH;

FIGS. 3A, 3B, 3C show sagittal cross-sectional views according to lineof FIG. 2 during subsequent treatment steps;

FIG. 4 illustrates a schematic of a cavity growing during tissuevaporization;

FIG. 5 illustrates a cross-sectional view similar to FIGS. 1 and 2, in afurther embodiment, during or prior to the treatment;

FIG. 6 illustrates the same view of FIG. 5 after treatment;

FIG. 7 illustrates a diagram showing the cavity volume increase duringtime;

FIG. 8 illustrates a view similar to FIGS. 3A-3B-3C of a furtherembodiment;

FIG. 9 illustrates a sagittal cross-sectional view of a prostate duringtreatment with trans-rectal ultra-sound (US) imaging guidance;

FIG. 10 illustrates a schematic cross-sectional view in a sagittal planeof a needle and optical fiber arrangement with improved gas removingfacilities, aimed at removing gaseous products resulting from thetissue/laser interaction and resulting tissue vaporization andsublimation;

FIG. 10A illustrates an enlargement of a detail of FIG. 10;

FIGS. 11 and 12 illustrate schematic cross-sectional views similar toFIG. 10 of further embodiments with improved gas removing facilities;

FIGS. 13 and 14 illustrate cross-sectional views according to lineXIII-XIII of FIG. 12 in two exemplar embodiments;

FIGS. 15A. 15B and 15C illustrate cross-sectional views according to asagittal plane in a further embodiment;

FIGS. 16, 17 and 18 illustrate flow-charts summarizing the main steps ofBPH treatment methods according to the present disclosure;

FIG. 19 illustrates a cross sectional view according to a sagittal planeof a prostate under treatment with the use of temperature sensors;

FIG. 20 illustrates a cross sectional view according to line XX-XX ofFIG. 19;

FIGS. 21A, 21B, 21C and 21D illustrate steps of a further methodaccording to the present disclosure;

FIG. 22 illustrates a modified step of the method of FIGS. 21A-21D; and

FIG. 23 illustrates a further modified step of the method of FIGS.21A-21D.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of exemplary embodiments refers tothe accompanying drawings. The same reference numbers in differentdrawings identify the same or similar elements. Additionally, thedrawings are not necessarily drawn to scale. Also, the followingdetailed description does not limit the invention. Instead, the scope ofthe invention is defined by the appended claims.

Reference throughout the specification to “one embodiment” or “anembodiment” or “some embodiments” means that the particular feature,structure or characteristic described in connection with an embodimentis included in at least one embodiment of the subject matter disclosed.Thus, the appearance of the phrase “in one embodiment” or “in anembodiment” or “in some embodiments” in various places throughout thespecification is not necessarily referring to the same embodiment(s).Further, the particular features, structures or characteristics may becombined in any suitable manner in one or more embodiments.

In embodiments disclosed herein, BPH is treated with a mini-invasiveprocedure using energy applicators introduced into the prostate throughthe trans-perineal route. Embodiments disclosed herein use laser energyconveyed in situ by means of optical fibers. The laser radiationparameters are selected such that water contained in the tissue isvaporized and other substances contained in the prostatic tissue cansublimate. The resulting gaseous by-products of the tissue/laserinteraction can be removed, possibly with the aid of ad-hoc removingdevices. Contrary to treatments of the current art, which are mainlybased on tissue denaturation and subsequent tissue resorption throughbiological action by the patient's body, an immediate reduction involume of the gland is achieved, which results in immediate relieve ofthe BPH symptoms, mainly linked to compression of the urethral lumen.

Turning now to the figures, FIGS. 1 and 2 illustrate two schematicsectional views along a transverse plane, i.e. orthogonal to thesagittal plane, of exemplary prostatic glands 1 affected by BPH. The twoglands 1 differ from one another as far as their total dimension isconcerned. The prostate of FIG. 1 is larger than the one of FIG. 2. Bothprostatic glands 1 contain adenomatous tissue 3, which has increased theoverall dimension of the gland and caused swelling thereof. The adenomacauses compression of the urethral lumen (urethra) 5, which extendsthrough the two lateral lobes 1A, 1B of the prostate. The prostate 1 issurrounded by a capsule 7. Neuro-vascular bundles 9 are arranged on theexterior of the capsule 7 on two sides of the prostatic gland 1.

Any surgical treatment of BPH shall prevent damages to the capsule 7 andthe neurovascular bundles 9, and possibly preserve the urethra for fastpost-surgical recovery.

In FIGS. 1 and 2 reference number 10 designates cavities which areformed in the prostate 1 by vaporizing and sublimating adenomatousprostatic tissue using laser energy. The laser treatment can beperformed by introducing one or more hollow needles or introducers inboth lobes 1A, 1B of the prostate and by introducing an optical fiberthrough each needle, such that laser energy can be delivered to theinterior of the adenomatous tissue causing vaporization thereof. The twolobes can be treated simultaneously. In other embodiments, each lobe canbe treated separately from the other, i.e. the two lobes can be treatedin sequence.

The needles and the optical fibers are introduced through the perineum,i.e. trans-perineally. The number of needles introduced in each lobe ofthe prostate 1 can depend upon the dimension of the prostate and uponthe amount of adenomatous tissue to be removed. Two or more needles orintroducers can be introduced at the same time in each lobe 1A, 1B ofthe prostate 1, such that adjacent or neighboring prostatic tissuevolumes can be treated simultaneously. In other embodiments, one or moreneedles or introducers can be introduced in sequence in the prostatictissue, for treating neighboring or adjacent volumes of the adenoma intimely shifted manner. This second approach will require a longertreatment time.

The number of simultaneously introduced needles can depend, inter alia,upon the number of laser sources available. It can be beneficial toprovide as many independent laser sources as there are simultaneouslyoperating optical fibers.

One or more needles or introducers and relevant optical fibers can bemoved during treatment along the needle axis, such that subsequenttissue volumes can be illuminated with laser energy in a so-calledpull-back procedure. With continuing reference to FIGS. 1 and 2, FIG.3A, 3B, 3C illustrate a sectional view according to line III-III of FIG.2, i.e. along a sagittal plane, in three different laser treatment stepsof the prostate 1. In the exemplary embodiment of FIGS. 3A, 3B, 3C twointroducers or needles 11, each guiding a respective optical fiber 13,are introduced in each lobe 1A, 1B of the prostate 1 through thetrans-perineal route. The needles 11 are introduced through the perineum15, i.e. through the area extending between the scrotum (not shown) andthe anus 17.

According to the embodiment shown in FIGS. 3A, 3B, 3C, each needle orintroducer 11 and relevant optical fiber 13 are fully introduced in theprostate up to the starting position of FIG. 3A, where the treatmentwill initiate. This is the position where the needle tips 11T arefarther away from the prostate apex 1C and nearest to the prostate base1D and to the bladder floor. The bladder is labeled 38. Laser energygenerated by a laser source is conveyed through the optical fibers 13 tothe tips thereof, which are located at or near the tips 11T of theneedles 11, or can project beyond said tips 11T.

As mentioned, according to some embodiments, independent laser sourcescan be provided for different optical fibers. In FIG. 3A one lasersource 19A, 19B is shown for each optical fiber 13. Each laser sourcecan be controlled independently from the others, such that for exampleeach laser source can be turned on or off and the laser emission thereofcan be adjusted independently from the others. For example the emissionpower, the emission time, the energy dose, the pulse frequency (in caseof pulsed laser) can be adjusted for each source independently. In otherembodiments each source can be coupled to multiple optical fibers. Insome embodiments, different laser frequencies, i.e. sources emitting atdifferent wavelengths can also be used in combination.

Insertion of the needles or introducers 11 and optical fibers 13, aswell as their subsequent movement in the prostate can be performed withthe aid of ultrasound imaging (US) using an ultrasound probe, forinstance a rectal probe, as described in greater detail later on. Inother embodiments, the insertion of the needles can be performed undermagnetic resonance imaging in combination with non-magnetic introducersor needles 11, or using any other suitable imaging method.

Laser emission can be controlled by a control unit 21, which can befunctionally connected to the laser sources 19A, 19B and to a userinterface 23. As will be described in more detail here on, a controlledamount of laser energy is delivered by the laser source through theoptical fibers 13 to cause vaporization and/or sublimation of tissue ina volume surrounding the tip of the optical fiber and/or in front ofsaid tip. In FIG. 3A, V1 indicates the volume of adenomatous tissuewhich can be vaporized and sublimated by the laser radiation while theoptical fiber tip is maintained in the position of FIG. 3A.

In order to remove a larger amount of tissue, the optical fiber 13 andthe relevant hollow needle or introducer 11 can be gradually moved outof the patient's body. For instance, once the tissue volume V1 has beenvaporized and/or sublimated by laser energy delivered through theoptical fibers 13 in the first position of FIG. 3A, the needles 11 andrelevant optical fibers 13 therein can be pulled back stepwise in anoutward direction f11, in the position of FIG. 3B. The hollow needles 11and optical fibers 13 can then be maintained in the new position of FIG.3B for a given amount of time, during which laser radiation generated bythe laser sources 19A, 19B irradiates the tissue in volume V2 and causesvaporization or sublimation thereof. Once the tissue in volume V2 hasbeen vaporized and/or sublimated, the needles 11 and optical fibers 13are moved a further step outward, until the position of FIG. 3C isachieved, where a third volume V3 of adenomatous tissue is vaporized orsublimated.

As can be appreciated from FIG. 3C, in a three-step process, twoelongate volumes of adenomatous tissue have been removed byvaporization/sublimation along the pull-back motion trajectory of thetwo needles 11 in lobe 1A. The same operation can be performedsimultaneously or subsequently in lobe 1B, such that at the end of theprocess, four volumes of tissue have been removed by vaporization and/orsublimation around the urethra 5. These four volumes are shown in across-sectional view in FIG. 2 and labeled V. The cavities thus formedwill contract and thus immediately relieve pressure on the urethra 5. Incontrast to so-called laser ablation techniques of the current art,which are based on tissue denaturation through laser radiation andsubsequent removal of the denaturated/desiccated tissue throughresorption, the treatment method of the present disclosure involves animmediate tissue volume reduction, with consequent immediate, real-timerelieve of compressive forces exerted by the adenomatous tissues on theurethral lumen. The real-time effect of laser ablation by vaporizationand/or sublimation of tissues through the transperineal route results invery fast recovery and short or no hospitalization.

As mentioned above, while in some embodiments all the needles 11 (fourin the exemplary embodiment of FIGS. 2 and 3) are introduced atsubstantially the same time, such that four cavities 10 corresponding tothe removed volumes V1, V2, V3 will form during the same treatment step,in other embodiments, the needles 11 and optical fibers 13 can beintroduced in sequence, thus forming the cavities in two or more steps.For instance, the needles in one lobe 1A, 1B can be introduced first,and only upon completion of the treatment of the first lobe, needleswill be introduced in the other lobe 1B, 1A. In other embodiments, afirst step may involve insertion of one needle per lobe and a secondstep, to be performed upon completion of the first step, may involveinsertion of the other needles in the two lobes.

Depending upon the dimension of the prostate 1 to be treated, adifferent number of hollow needles or introducers 11 and of opticalfibers 13 can be used. In FIG. 1 two cavities 10 are formed by usingjust two needles 11, one per lobe 1A, 1B.

The dynamics of laser ablation by vaporization and/or sublimation withnaked optical fibers involves the formation of a cavity ofsublimated/vaporized tissue, surrounded by a small layer of vacuolatedand dehydrated tissue. For a frontal-emission optical fiber 13 thecavity of vaporized tissue grows with respect to energy delivery time,i.e. as a direct function of the energy dose.

FIG. 4 pictorially illustrates cavity formation from the beginning tofinal saturated dimension. If the laser radiation intensity is above thetissue vaporization and sublimation threshold, a cavity Cl starts toform and grows in front of the fiber tip 13T. The laser energy isabsorbed by the water contained in the tissue and causes vapor formationat the tip of the optical fiber 13.

In FIG. 4 the shape of the cavity is the one obtained with an opticalfiber having a flat fiber tip, which produces a cavity of ellipticshape. As laser emission continues, the laser emission will furtherpropagate through the empty volume formed by vaporization of the tissuesuch that the front of the tissue, i.e. the inner surface of the cavity,moves forward, away from the fiber tip. Tissue is, dehydrated andvaporized and finally sublimated in a cyclic way leading to awell-defined cavity in front of the fiber tip. As time proceeds, thecavity enlarges from Cl to C6.

As the volume of the cavity increases, the front velocity, i.e. thespeed at which the surface of the cavity advances in front of thestationary fiber tip 13T moving away therefrom, decreases as pictoriallyrepresented by cavities C3, C4, C5, C6. The reason for this is that theenergy per surface, which impinges on the forward moving cavity surface,reduces with the square of the distance from the fiber tip. The speed ofablation by vaporization and sublimation slows down until an asymptoticlimit is achieved. When the cavity achieves the dimension represented byC6, whose size (length and the maximum diameter) depends on the chosendose (duration of the treatment multiplied by the mean power value), thepower density at the cavity margin is not able to sustain the process ofvaporization and a stable condition is achieved in terms of removedvolume, i.e. no further tissue can be vaporized and removed, such thatthe dimension of the cavity remains constant and the fiber is to beswitched off.

When the dimension C6 is achieved, the needle or introducer 11 and theoptical fiber 13 therein can be withdrawn stepwise with a pull-backmaneuver as described above, such that an adjacent tissue volume can betreated in the next treatment step.

Since the parameters of the laser emission are chosen such that theirradiated tissue is removed by vaporization and sublimation, the reliefof the compression exerted by the hypertrophic prostatic tissue on theurethral lumen 5 is rapidly obtained as can be understood from FIGS. 5and 6. An additional brief rectal internal massage of the prostateoperated by a finger can improve the effect by promoting or acceleratingcollapsing of the tissue around the cavity thus formed.

In FIG. 5 a schematic sectional view of the prostate 1 during orimmediately after laser application is shown. One or more cavities 10are generated by tissue vaporization and sublimation. In the exemplaryembodiment of FIG. 5 five cavities 10 have been formed in each lobe 1A,1B of the prostate 1. The tissue around the cavities 10 will collapsespontaneously or helped by a short rectal massage, such that thecavities 10 will shrink, as shown in FIG. 6. Shrinkage of the cavitiescauses a reduction of the external volume of the prostatic gland 1 and areduction of the urethra compression. The urethra 5 re-opens as a directconsequence of the resulting pressure relieve thereon.

From an experimental work ex vivo with an optical camera it was possibleto measure the length (i.e. longitudinal dimension) of the cavity duringits formation and the cavity dimension versus time could be plotted.FIG. 7 illustrates the cavity length vs. time. The dotted linerepresents the position (distance from the fiber tip) of the activefront of the cavity. The continuous line is an exponential fitting curveof the raw data. Lasing starts at time 0. The data of FIG. 7 wereobtained with a continuous laser beam with a power of 5 W, 1064 nm laserwavelength, conveyed through a quartz optical fiber with flat tip and acore diameter of 300 micrometer. The experimental data were obtainedusing a fresh porcine liver sample at room temperature.

At the beginning of the laser emission, for about 40 seconds, there isno movement in the forward direction, i.e. no cavity is formed in frontof the fiber. This time is necessary to heat the tissue above 100° C.and activate intra and inter cellular water boiling and subsequent vaporformation in front of the fiber. If treatment stops before the vaporformation threshold is achieved, a spherical coagulated thermal lesionis created in the tissue, centered on the fiber tip. Once thevaporization threshold is achieved and exceeded, a cyclic action ofdehydration, vaporization and sublimation occurs on new tissue layersfacing the laser radiation emitted by the fiber tip. The active front ofthe cavity being formed moves forward in an asymptotic way (as describedby the continuous fitting line in the graph of FIG. 7, up to saturationof the cavity length. This means that there is no further cavityenlargement even if energy delivery continues. This saturationphenomenon is dependent upon the slight divergence of the optical fiberemission. This means that the power density i.e. the radiation intensitydecreases as the distance of the cavity surface from the fiber tipincreases. In the asymptotic condition the power density decreases to avalue that is under the vaporization threshold and hence the laserradiation is unable to induce further tissue removal. Once thiscondition is achieved, further energy delivered by the fiber isdissipated by thermal conduction to surrounding tissue and by bloodperfusion.

The vaporization and sublimation threshold depends on the powerintensity at the output of the optical fiber and therefore depends onthe input power, the emission surface, and the dose, i.e. the amount ofenergy needed to give rise to the phenomenon. The wavelength alsobecomes important, because it determines the type of interaction betweenlaser radiation and tissue. In particular the radiation absorptioncoefficient varies with the wavelength. For instance, for a laserradiation having a wavelength of 1064 nm, a power of 2 W (continuouswave) is sufficient to achieve tissue sublimation and vaporization andcavity formation with an optical fiber having a core diameter of 300micrometers.

The lower power threshold to achieve vaporization and sublimation on aspecific tissue depends on the power, energy delivery mode (continuousor pulsed), fiber tip (dimension and shape), absorption and scatteringcoefficients, which in turn depend on tissue and wavelength combination.The higher the power used, the faster the cavity formation speed. At1064 nm the preferred power values are from 3 to 7 W in continuous wavemode.

The ratio between power and fiber tip surface defines the emittedradiation intensity. For 5 W delivered by a 300 micrometer core fiberdiameter, the intensity is 17.7 W/mm². Intensities should be above 1W/mm² to excite cavity formation with a 1064 nm wavelength andcontinuous wave with a dose of 1200-1800 J. With other laser wavelengthsintensities are different and can be easily re-assessed.

Doses range from a few hundreds to a few thousands Joule. The optimalresults are obtained from 600 J to 1800 J. There is a linearrelationship between cavity volume and dose in this range. Doses greaterthan 1800 J induce a slight and not interesting increase in cavityenlargement.

According to some embodiments, for instance using a 5 W laser power anda wavelength of 1064 nm, the time required to start formation of acavity in the tissue can be around 40 seconds, which correspond to anenergy dose of 200 J. A first heating step precedes the actual tissuevaporization and cavity formation. The initial heating step is needed tobring the vaporization of water contained in the tissues. The firstheating step is followed by cavity formation with a cavity volume whichincreases asymptotically. After a dose of 1800 J has been delivered(approximately 6 minutes) the maximum cavity volume has been achieved.Continued laser radiation with the fiber tip in the same position willnot lead to any significant increase in the cavity volume.

The cavity formation process can be monitored by an ultrasound probe,exploiting the variable echogenicity of the tissues. During the firsttreatment step, preceding vaporization, the lased tissues will have anegligible echogenicity variation. The echogenicity will increase whenvapor bubbles start developing. The echogenicity variations can bedetected through an ultrasound probe. According to other embodiments,cavity formation can be monitored by Magnetic Resonance Imaging (MRI) orComputer Tomography (CT) imaging and can be detected as change in thetissue density. A combination of various imaging techniques is not ruledout.

Laser wavelengths that can be employed can be for instance those, whichcan be guided by optical fibers or wave guides usually in the visibleand near infrared region. In some embodiments UV radiation can be usedas well. According to the absorption spectrum, different wavelengthsinteract with different chromophores or water contained in the tissue.Thus, for each laser wavelength a set of lasing parameters should beevaluated in order to obtain tissue removal by vaporization andsublimation (i.e. vaporization and sublimation threshold should beevaluated for each configuration of lasing parameters in order toproduce a cavity in a specific tissue). E.g. ablation parameters can beadjusted based upon the wavelength used. In some embodiments, a 10.6 μmlaser radiation generated by a CO₂ laser source can also be used aswaveguide are now available, which can guide also this radiationwavelength. According to other embodiments the following laser sourcescan be used: Nd:YAG laser emitting at 1064 nm; thulium laser emitting at2010 nm; holmium lasers emitting at 2100 nm. Other suitable lasersources can include herbium laser at 2940 nm, using a hollow waveguide.

In some embodiments, different laser sources can be used in combination.

In some embodiments, the laser radiation can be continuous. In otherembodiments a pulsed laser source can be used. Tests ex-vivo have beencarried out with a pulsed holmium laser source using porcine livertissue maintained at 20° C. (+1-5° C.) in a thermostatic bath. Thistemperature value was chosen with reference to the physiological in vivovalue (about 37° C.). The operating temperature used during ex-vivotests was reduced to 20° C. in order to take into consideration theabsence of local blood perfusion which, in a living body, enables localheat removal during laser treatment. A holmium laser source with awavelength of 2100 nm and pulsed emission was used in combination with aquartz optical fiber with a 550 micrometer core diameter.

Different pulse repetition frequencies and pulse amplitudes have beentested. Specifically, pulse repetition frequencies from 1 Hz to 20 Hzhave been used, in combination with pulse amplitudes ranging from 0.2Joule to 2 Joule. Different combinations of pulse repetition frequencies(PRF) and pulse amplitudes result in different power values. Thefollowing table summarizes different trials performed with differentpulse repetition frequencies, pulse amplitude values, power, energydoses and treatment times (value in bold are constant for subgroup ofexperimental tests). The last column reports the dimensions of thecavity obtained in the liver tissue (length and width in millimeters):

Exposure Cavity Pulse Dose Time Cavity dimension Sample PRF Energy Power[Joule] [s] formation [mm × mm] #1 20 Hz 0.5 10 W 1200 120 Yes 14 × 6 #2 20 Hz 0.5 10 W 900 90 Yes 16 × 5  #3 20 Hz 0.5 10 W 600 60 Yes 10 ×3  #4 20 Hz 0.5 10 W 300 30 Yes 9 × 3 #5 20 Hz 0.5 10 W 100 10 Yes 7 × 3#6 20 Hz 0.4  8 W 100 12.5 Yes 5 × 2 #7 20 Hz 0.3  6 W 100 16.7 Yes 5 ×2 #8 20 Hz 0.2  4 W 100 25 Yes 5 × 2 #9 20 Hz 0.4  8 W 80 10 Yes 8 × 3#10 20 Hz 0.3  6 W 60 10 Yes 7 × 2 #11 20 Hz 0.2  4 W 40 10 No NA #17  5Hz 2 10 W 100 10 Yes 8 × 3 #13 15 Hz 1 15 W 100 6.7 Yes 6 × 2 #12 15 Hz0.5 7.5 W  100 13.3 Yes 7 × 2 #14 10 Hz 0.5  5 W 100 20 Yes 8 × 2 #16  5Hz 0.5 2.5 W  100 40 Yes 6 × 2 #15  1 Hz 0.5 0.5 W  100 200 No NA

According to exemplary embodiments of the laser ablation methoddisclosed herein, the emission parameters may be maintained constantduring the entire treatment time. However, this may not always bepossible or preferred. In some embodiments, the laser ablation treatmentcan be performed with a gradually increasing emission power, forinstance to prevent tissue explosion due to abrupt vapor formation. Inother embodiments, higher power values can be used at the beginning ofthe treatment, before the tissue cavity starts forming, followed bylower power emission, which can be used to promote hemostasis.

When pulsed laser emissions are used, the pulse repetition frequency, orpulse repetition rate, and the energy per pulse can be used as furtherselectable and adjustable parameters. The same mean power can be indeedachieved with different combinations of pulse repetition rates andenergy per pulse. However highly energetic pulses with a low pulserepetition rate will have a different effect on the treated tissue thanpulses having a lower energy but a higher repetition rate.

As mentioned, the method involves the use of one or more fibers 13 thatare trans-perineally introduced in the prostate by means of thin needlesor introducers 11. The more fibers are placed inside the lobes 1A, 1B ofthe prostate 1 the quicker and more effective the treatment will be. Theoptimal trade-off between effectiveness and time duration consists ofsimultaneous energy delivery, which involves one or two fibers 13 andrespective introducers 11 per lobe (thus from two to four optical fibers13 for the whole gland) as shown in FIG. 2. However, a smaller number offibers (FIG. 1) or a larger number of fibers (FIGS. 5 and 6) can beused.

Two or more adjacent cavities may merge into a single cavity, if sodesired. The treatment can also be performed with a single fiber andwith multiple illuminations and repositioning.

According to the cavity shape, which depends upon several parameters,such as shape of the fiber tip, power, dose, absorption coefficient, itis possible to define safety criteria for the fiber tip positioning. Asa matter of fact, the fiber tip can be placed at a safety distance fromcritical structures inside, around and adjacent the prostate 1, such asthe urethral lumen 5 inside the prostate 1, the capsule 7 around theprostate 1 and the two neurovascular bundles 9 outside and adjacent theprostate 1.

According to some embodiments, using a 3 W continuous wave power with aflat tip optical fiber the following safety rules can be applied:lateral distance equal to or larger than 5 mm (optimal distance 10 mm);front distance between the fiber tip and the capsule 7, at least 15 mm.Higher power can be used with redefinition of the safety criteria.Higher power levels generate longer cavities. Thus, a larger safetydistance between the fiber tip and the prostate base 1D (front distancebetween capsule and fiber tip) should be adopted.

The mutual distance between fibers 13 depends on how many cavities C areplanned to be formed in the tissue. Usually said mutual distance rangesbetween 5 mm and 15 mm depending upon total prostate volume and otherconstrains imposed by the above mentioned safety criteria (distance fromcapsule and urethra, for instance).

At 5 W power, safety distances should be re-assessed, especially as faras the front distance, i.e. the distance between the capsule and thefiber tip is concerned.

Depending on the prostate volume and in particular the longitudinallength, from base to apex, it is possible to gradually and stepwisewithdraw the needles 11 and optical fibers 13 and perform a laserradiation at each newly reached position (pull-back maneuver), asdescribed above in connection with FIGS. 3A-3C. This allows maximizingvolume removal with a single needle insertion. The extension of eachwithdrawal movement, i.e. the length of the needle 11 and the fiber 13which is extracted from the prostate 1 at each pull-back maneuver, canbe assessed by the aid of an ultrasound or magnetic resonance imagingsystem or by ticks on the needle cannula.

In some embodiments, the treatment can start with the fiber tipspositioned at 15 mm from the capsule (prostate base) in the frontdirection and after a first energy delivery, if the apex-to-basedistance allows it, the needle can be pulled back and a new dose oflaser energy can be delivered in the new fiber position. The number ofpull-back movements is related to the apex-base dimension of the gland1. The greater the number of pull-back steps, the greater the amount oftissue removed from the gland 1. For each insertion of the fibers thetreatment stops when it is not possible to withdraw the fiber further,based on the safety rule, as the minimum distance between capsule andfiber tip must be respected.

The method can be carried out with optical fibers having a flat tip. Inother embodiments, however, special optical fibers, having a differentgeometry, can be used. Special optical fibers may have a special tipshape obtained by chemical etching, mechanical lapping, thermal fusionor other chemical, physical or mechanical treatment.

In some embodiments, the optical fiber may be adapted to achieve sidefiring or globular firing. As used herein, the term “side firing opticalfiber” can be understood as an optical fiber which emits at least oneoptical beam from the side surface thereof. As used herein, the term“globular firing optical fiber” can be understood as a fiber having atip shaped such as to generate a substantially globular or sphericalemission.

In some embodiments, globular firing can be obtained with an opticalfiber having a conical tip, rather than a flat, planar tip. A globularfiring optical fiber can generate substantially spherical cavities inthe tissue. FIG. 8 schematically illustrates a cross sectional viewaccording to a sagittal plane of a prostate 1 under treatment, similarto FIGS. 3A-3C. The same elements are labeled with the same referencenumbers as in FIGS. 3A-3C and will not be described again. In theembodiment of FIG. 8 the optical fiber tip 13T is shaped such as to havea globular, i.e. substantially spherical emission, which generates asubstantially isotropic energy distribution on a spherical surface. Thisresults in a spherical volume V1 of tissue vaporization and sublimationand consequently generates a substantially spherical cavity. V2, V3, V4indicate ablation volumes which are obtained in subsequent pull-backsteps, during which the introducers 11 and the optical fibers 13 guidedtherein are gradually withdrawn from the prostate 1.

The mechanism of tissue removal remains the same as described above. Thecyclic dehydration, vaporization and sublimation process takes place onenlarging spherical surfaces due to isotropic energy deliver energy.Spherical cavities are more suitable for treatments in small organs andclose to critical vital structures, because of the geometrical shape ofthe spherical cavity formed, the surface whereof is maintained atsubstantially the same distance from the fiber tip 13T in alldirections. In other words, the shape of the cavity generated by laservaporization or sublimation of the tissues is not related to thedirection of insertion of the needles, contrary to what happens whenoptical fibers with a flat tip are used, which generate ellipticcavities.

Also with globular firing optical fibers laser power and energy can beset at 3 W and 1800 J, respectively, for a 1064 nm wavelength lasersource operating in a continuous wave mode. In this case, the abovementioned safety rules setting the minimum distances between the tips ofthe optical fibers and the critical structures inside, around andoutside the prostate must be adapted to the new shape of the cavity thatis produced. In some embodiments using a globular (spherical) firingoptical fiber with a 5 W laser source, the tip 13T of each optical fiber13 should be at least 1 cm from the critical structures (urethra,capsule) even in the transverse direction.

The use of isotropic or quasi-isotropic radiators (optical fiber tips13T) allows using higher power ranges than those which can be appliedusing free handle flat-tip optical fibers. The safety distances betweenfiber tip and critical structures of the prostate should be reassessedfor each case.

As mentioned above, positioning of the needles or introducers 11 can beperformed under imaging guidance, for instance under ultrasound guidancepreferably with a trans-rectal probe and preferably with a bi-planeprobe. A bi-plane probe allows displaying images according to transverseand longitudinal (sagittal) planes of the prostatic gland. FIG. 9 showsa sectional view according to a sagittal plane of a prostate duringinsertion of two needles 11 in one of the lobes 1A, 1B of the prostate1, using US (ultrasound) imaging guidance. An ultrasound (US)trans-rectal probe 31 can be inserted into the rectum and allows imagingthe portion of interest. The US trans-rectal probe 31 can be connectedto an ultrasound imager 33, which can be provided with a display 35. Thetrans-perineal insertion of the needles or introducers 11 can beperformed freehand or through a needle guide device 37 connect to thetrans-rectal probe 31.

The US trans-rectal probe 31 can be maintained in place also afterinsertion of the needles 11 and optical fibers 13, during part of thetreatment or during the entire treatment. Ultrasound imaging can be usedto control whether tissue vaporization or sublimation and the formationof the cavity in the gland tissue proceeds correctly. Additionally, incase of pull-back maneuver, as described above in connection with FIGS.3A, 3B, 3C, US imaging can assist the operator to retract the needles 11by the required length at each pull-back step, such that subsequentlyremoved tissue volumes merge in a single, longitudinally extending emptycavity formed in the gland tissue.

A catheter 36 can be placed into the urethra up to the bladder 38 priorto start treatment of the prostate 1, to provide a reference point inthe US image shown on the display 35.

In some embodiments of the method disclosed herein, removal of gaseousby-products, generated by vaporization and/or sublimation of the lasedgland tissues may be particularly beneficial. Removing gaseousby-products generated by interaction of the laser radiation with thegland tissue may promote and facilitate the entire tissue removalprocess. Vapor or other side products which are not removed areotherwise slowly absorbed by microcirculation and blood perfusion, aprocess which takes some time until complete elimination is obtained.Removal of the vapor or other side products through the needles duringlasing or after lasing but prior to removing the needles from theprostate can substantially accelerate the reduction of the prostatevolume and thus the relieve of the pressure applied by the prostatictissue on the urethra 5.

During lasing and gas formation caused by tissue vaporization orsublimation, a positive pressure is generated inside the cavity formedby the laser radiation. The gas can flow through an annular gap betweenthe optical fiber 13 and the inner surface of the needle 11, thusescaping from the needle hub. For this reason, according to someembodiments, the coupling between needle hub and optical fiber hub iskeep opened. In other embodiments, selectively closable and openableports can be provided, for gas or vapor venting purposes. A possiblecoupling system with grooves for gas discharge is disclosed in U.S. Pat.No. 8,265,446, the content whereof is entirely incorporated herein byreference.

According to some embodiments, improved removal capability of the needleshaft or introducer cannula 11 can be achieved by providing side holesor ports in the wall of the needle close to the tip thereof. These sideholes or ports can prevent obstruction of the main channel of the needlein case solid particles and debris are present in the cavity generatedby laser radiation.

FIGS. 10 and 10A schematically illustrate a needle or introducer 11 witha needle hub 11A and a needle tip 11T. An optical fiber 13 is introducedthrough the needle 11 and the emitting fiber tip 13T is located in acavity being formed by lasing the surrounding prostatic tissue. Thecavity C contains pressurized vapor or gaseous side-products generatedby the vaporization or sublimation of the tissue. The gas escapesthrough the annular gap between the optical fiber 13 and the innersurface of the needle 11. The fiber hub is shown at 13A and at least oneventing port is available between the fiber hub 13A and the needle hub11A, such that gas G can escape from the cavity C. In FIG. 10A, whichshows an enlargement of the needle and fiber tip area, side holes 11Hnear the needle tip 11T are provided, which facilitate gas or vaporremoval, should the end of the needle become clogged by solid orhigh-density liquid debris.

In some embodiments, improved efficiency can be achieved by promotinggas and vapor extraction from the cavity being formed in the prostatetissue. According to some embodiments, a pressure reduction can begenerated in the interior of the needles 11, for instance by means of asuction device, such as a vacuum pump or the like.

With continuing reference to FIG. 10, in FIG. 11 a vacuum pump 41 isfluidly coupled to the interior of the needle 11. The pump 41 is adaptedremove gas or vapor by depressurizing the interior of the needle, andmore specifically the annular gap between the needle 11 and the opticalfiber 13. The negative pressure in the needle 11 can be enough toaspirate gas or vapor from the cavity C being formed by the laserradiation in the prostate tissue, such that the pressure in the cavity Cis maintained under control. A first duct 43 can fluidly couple theinterior of the needle 11 to a collecting tank 46. The latter can befluidly coupled to the vacuum pump 41 through a duct 45. Particles orcondensed vapor can be collected in the tank 44 and prevented fromreaching the vacuum pump 41.

According to further exemplary embodiments, a double way introducer orneedle 11 can be used, in order to apply suction to a first passagewayand refill the cavity under formation with fresh air through the secondpassageway. This can be beneficial in order to fully remove from thecavity C gases or vapors that can interfere with the laser radiation,thus decreasing the effectiveness of laser-to-tissue interaction.

With continuing reference to FIGS. 10 and 11, FIG. 12 illustrates anembodiment wherein a two-way introducer or needle 11 is used incombination with suction and fresh air feeding inside the cavity C beingformed during laser vaporization or sublimation of the lased prostatetissue. The same reference numbers used in the previous figuresdesignate the same or corresponding parts or elements, which are notdescribed again. FIGS. 13 and 14 illustrate cross-sectional viewsaccording to line XIII-XIII of FIG. 12, of two exemplary embodiments ofa two-way needle or inserter 11. The needle 11 may comprise an externalcannula 11X and an internal tubular element 11Y. The optical fiber 13can be housed in the internal tubular element 11Y in a substantiallycoaxial position therewith. In some embodiments (FIG. 13) distancing andcentering members 55 can be arranged between the cannula 11X and theinner tubular element 11Y. A first annular passageway 51 is thus formedbetween the cannula 11X and the inner tubular element 11Y. A secondannular passageway 53 is formed between the inner tubular element 11Yand the optical fiber 13.

Referring to FIG. 12, a duct 57 can be in fluid communication with theenvironment and with the first pathway 53. An air filter 59 can preventpollutants, and pathogens, such as micro-organisms, from entering theneedle passageway 53. The second passageway 53 is fluidly coupled to theduct 43 and thus, through the collector tank 44 and the duct 45, withthe suction or vacuum pump 41.

The device illustrated in FIGS. 12, 13, 14 operates as follows. Once theneedle 11 has been placed in the correct position inside the prostate,possibly with the aid of US imaging or other imaging facility, the lasersource is activated and laser radiation interacts with the tissuesurrounding the tip 13T of the optical fiber 13, causing vaporizationand/or sublimation of the tissue and thus forming a cavity C ofgradually increasing volume. The vacuum pump 41 removes gaseous matterfrom the cavity C under formation through the second pathway 53 of theneedle, and the negative pressure generated in the cavity C causes freshair to enter the cavity through the air filter 59, the duct 57 and thefirst passageway 51 of the needle 11. The gaseous matter removal and aircirculation can continue for the entire cavity formation step, such thatthe cavity C will be free or substantially free of laser absorbinggaseous side products generated by laser-tissue interaction. This may bebeneficial in terms of speed of treatment and dimension of the cavity Cobtained for each position of the needle or introducer 11.

According to yet further embodiments, enhanced BPH treatment results canbe achieved by combining tissue ablation through vaporization with amechanical action through the urethra 5. In some exemplary embodiments,an inflatable balloon can be introduced in the urethral lumen 5 of thepatient prior, during or after insertion of the needles 11.

With continuing reference to FIGS. 1 to 14, FIGS. 15A, 15B and 15Cillustrate a cross sectional view along a sagittal plane of the prostateduring treatment with optical fibers introduced trans-perineally in theprostate and one or more inflatable balloons placed in the urethra 5.

In FIG. 15A an elongated inflatable balloon 61 has been positioned inthe urethra 5 of the patient by means of a catheter 62 or through anyother suitable means. Once the balloon 61 is placed in the correctposition, it can be inflated, for instance with a physiologic solutionat suitable pressure and temperature conditions. Inflatable balloons forangioplasty or similar surgical applications are known, and they can beadapted for use in the method disclosed herein.

Upon inflation, the balloon 61 causes compression of the surroundingtissue of the prostatic gland and dilation of the urethra 5 at itsphysiologically normal conditions, or even beyond the physiologicallynormal dimension of the urethral lumen 5. Compression of the surroundingtissues can facilitate evacuation of the gaseous or vapor by-productsgenerated by laser-tissue interaction and tissue vaporization orsublimation.

In addition, due to a thermo-plastic effect, once the balloon 61 isdeflated and removed from the urethra 5, the surrounding tissues will atleast partly maintain their compressed condition, thus providing moreefficient relief to the urethra 5 immediately after treatment.

In some embodiments, the filling fluid used to inflate the balloon 61can be circulated, to maintain the fluid temperature under control. Insome embodiments, the fluid temperature can be maintained above basaltemperature, e.g. around 40-42° C. In other embodiments, the fluidtemperature can be maintained at a lower temperature, even below thebody temperature. Temperature control and fluid circulation can be usedto cool the urethra 5 and the tissue immediately surrounding theurethra, preventing damages due to over-heating.

In the embodiment of FIG. 15A a single balloon 61 with an enlarged headend 61A is retained in the correct position by introducing the balloon61 in the urethra 5 until the head end 61A thereof reaches the bladder38.

In FIG. 15B, with continuing reference to FIGS. 1-15A, an inflatableballoon 61 is used, which has an elongated central body and two expandedends 61A, 61B. These latter provide for a precise and correctpositioning of the balloon 61 in the urethra 5 and contribute inmaintaining the inflated balloon 61 in the correct position duringlasing of the prostate 1.

In FIG. 15C, with continuing reference to FIGS. 1-15B, two inflatableballoons 61X, 61Y are used in combination with one another. The firstballoon 61X can be introduced in the bladder 38 and the second balloon61Y can be positioned in the urethra 5. The two balloons 61X, 61Y can beintroduced by means of the same catheter 61 and the balloon 61X providesfor safe positioning of the second balloon 61Y in the urethra 5.

Balloons 61 of different shapes and/or dimensions can be selected by theoperator based upon the dimension of the prostate 1 to be treated, theanatomic features of the patients, or other factors.

FIGS. 16, 17 and 18 show three flow-charts which summarize exemplarymethods of treating BPH disclosed herein.

In some embodiments, treatment safety can be increased by addingtemperature control facilities, for instance, aimed at preventingover-heating of critical structures inside or around the prostate 1under treatment.

Referring to FIGS. 19 and 20, with continuing reference to FIGS. 1 to15C, temperature sensing arrangements 71 can be introduced in theprostate 1 under treatment in combination with needles 11 and opticalfibers 13. Thermocouples, thermoresistors or temperature measuringfibers can be introduced through needles or cannulae in the prostate. InFIGS. 19 and 20 reference number 71 indicates any possible kind oftemperature measurement device, apparatus or arrangement. For instance,a pervious needle or a cannula can be used to introduce a thermocoupleor a thermoresistor near critical areas of the prostate 1. In someembodiments an optical fiber with a Bragg grating can be used insteadof, or in combination with thermocouples and/or thermoresistors.

In some embodiments, the temperature sensitive portion of thetemperature sensing arrangement can be located at or near the tip of thetemperature measuring device 71. In other embodiments, temperaturesensing areas can be located in several positions along the axialextension of the temperature measuring device 71, for example if opticalfibers with a Bragg grating are used. These latter are able to detectthe temperature at different depths in the prostate, for exampleparallel to the axial extension of the needles 11.

In FIGS. 19 and 20 two temperature sensing or measuring devices 71 areintroduced in the prostate 1. A first temperature sensing or measuringdevice 71 is positioned between the urethra 5 and the area where a firstcavity 10 will be generated by a first optical fiber 13. A secondtemperature sensing or measuring device 71 is arranged between theneuro-vascular bundle 9 and the area where a second cavity 10 will begenerated by a second optical fiber 13. Thermal damages of the urethra 5and of the neuro-vascular bundles 9, due to over-heating or excessivelaser radiation, can thus be prevented. The temperature measuring orsensing devices 71 can be functionally coupled to the control unit 21,such that the emission parameters of the laser sources 19A, 19B can bemodulated automatically to maintain the tissue temperature under controland prevent thermal damages of critical structures in and around theprostatic gland 1. For instance the control unit 21 can be adapted toreduce the mean power, or the peak pulse energy, or other laser emissionparameters, if the temperature measured by at least one of thetemperature sensing or measuring devices 71 increases above a givensafety threshold. In some embodiments, one or more temperature sensingor measuring devices 71 can be combined with some or each one of theoptical fibers 13, such that each or some of the laser sources 19A, 19Bcan be automatically controlled through data from the temperaturesensing or measuring devices 71 combined with the respective opticalfibers 13.

In other embodiments, temperature information from the temperaturesensing or measuring devices 71 can be made available to the operator,for instance through a suitable user interface, such as a display ormonitor. The operator will then manually modify the laser emissionparameters based on the temperature information from the temperaturesensing or measuring devices 71.

According to a further aspect, the disclosure also concerns a method ofreducing a volume of a benign or malign tumor in an organ of a patientin need of said treatment. According to a yet further aspect, thedisclosure concerns a method for removing tissue from an organ of apatient according to a mini-invasive technique.

According to some embodiments, the method comprises the following steps.A first step involves the introduction of at least one energy deliverydevice in a first position in an organ of the patient. The energydelivery device can include an optical fiber coupled to a laser source.The optical fiber can be introduced through a needle or introducer. Oncethe energy delivery device has been placed in the correct position,possibly with the aid of an ultrasound or other imaging device, themethod comprises the step of delivering energy from an energy sourcecoupled to the energy delivery device. The energy is delivered throughthe energy delivery device to a first volume of tissue of the organ, inwhich the energy delivery device has been positioned. Energy isdelivered until at least a portion of the first volume is vaporized orsublimated and a cavity is formed in the organ tissue. According to someembodiments, during or after energy delivery, gaseous side-productsgenerated by tissue vaporization or sublimation can be removed, e.g. bysuction, as described above. The method further includes the step ofremoving the energy delivery device from the organ. If needed, prior toremoving or after removing, the energy delivery device can bere-positioned in a different position inside the organ, to repeat theabove steps and remove by vaporization and/or sublimation a furtherportion of tissue.

The tissue can be hard tissue, such as bone or the like, or soft tissue,such as liver, thyroid, pancreas, brain, or other organs which may needtreatment. In particular if soft tissue is treated, the volume of thecavity thus formed can be reduced, e.g. by massage on the organ.

According to some embodiments, the method can further include the stepof introducing in the cavity formed by tissue vaporization orsublimation, at least one medically active element. In some embodiments,the method includes the step of introducing in the cavity thus formed atleast one of the following: a medicament, a drug, a slow-absorptiondrug, a radioactive seed, such as a seed for brachytherapy, achemotherapeutic agent, a combination thereof. The method allows forminga cavity in the organ to be treated without resorting to cuttinginstruments, which would destroy also portions of healthy tissuesurrounding the area where the tumor to be treated is positioned.

While in some embodiments the tissue to be removed can be a benign ormalign tumoral tissue, the method is not limited to removal of tumoraltissue. More in general, a mini-invasive surgical method is disclosed,aimed at generating a cavity in an organ in a body of a patient, forinstance an organ which is difficult to reach. The method disclosedherein suggests a new way of mini-invasively reaching the site wheretissue is to be removed, reducing as far as possible any impact on thesurrounding tissue. This can be of paramount importance, for instance,when the need exists to preserve the integrity of surrounding tissue,such as in brain surgery.

FIGS. 21A, 21B, 21C, 21D pictorially illustrate steps of a methodinvolving tissue removal in a generic organ 101 through an introducer 11and an energy delivery device 13. In the exemplary embodiment of FIGS.21A-21D the introducer 11 includes a hollow needle and the energydelivery device 13 includes an optical fiber. The energy source mayinclude a laser source. In FIG. 21A the introducer 11 and the opticalfiber 13 have been introduced through surrounding tissue 102 in theorgan 101 to be treated. In FIG. 21B a cavity 103 has been generated byenergy-tissue interaction and tissue vaporization and/or sublimation.Resulting gaseous by-products can be removed as described above, throughthe introducer 11.

In FIG. 21C the optical fiber 13 has been removed, while the introducer11 is still in place. The cavity 103 has been generated in the organ101. In a further step of the method a basket, for example a shapememory basket 105, 105A can be introduced through the introducer 11 andthe head 105A thereof can be expanded in the cavity 103, to prevent thecavity 103 from collapsing. FIG. 21D illustrates the expanded basket105, 105A. Expandable baskets useful in the present method are known inthe art. A basket is disclosed in US20180042625.

According to some embodiments, using a basket 105, 105, the cavity 103can be maintained in the expanded status, for instance, in order tofacilitate introduction therein of a medium, such as a liquid orsemi-liquid medium, such as a drug carrier.

In some embodiments, a different medium, such as a solid medium can beintroduced in the cavity. For instance, radioactive seeds forbrachytherapy can be placed in the expanded cavity 103.

The basket can be recoverable. The method can thus include a step ofintroducing basket in the cavity generated by tissue vaporization orsublimation and a subsequent step of removing the basket from thecavity. According to other embodiments, the basket can be left in thecavity and can be made of absorbable materials.

According to some embodiments, nanoparticles, for instance gold oriron-based nanoparticles as drug carriers can be introduced in thecavity 103. Drugs, such as monoclonal drugs, for instance monoclonalantibodies can be introduced in the cavity 103, possibly attached tosuitable carriers, such as nanoparticles.

Drugs or medicaments can be conveyed in a liquid or semi-liquidsuspension. An expandable basket 105, 105A can prevent cavity reductionand facilitate the insertion of the suspension. In some embodiments, thebasket can be retained in place until the drug has been absorbed.

In other embodiments, for instance if a semi-liquid or highly viscouscarrier is used, a basket may be dispensed with or may be removed soonafter inoculation of the drug suspension.

FIG. 22 illustrates a cross sectional view similar to FIGS. 21A-21D,wherein the cavity 103 has been filled with a liquid, semi-liquid or gelsubstance 107. The substance 107 may contain a drug or medicament, andmay in turn comprise particles, such as nanoparticles used as drugcarriers. The filling substance can be introduced through the introducer11 or through a cannula inserted into the organ 101. The introducer 11can be used also for the insertion of the basket 105, 105A. In someembodiments, the basket 105, 105A can be removed along with theintroducer 11 from the organ 101 upon injection of the substance 107.The tissue wall surrounding the introducer or needle 11 can collapseafter removal of the needle 11, such that reverse flow of the substance107 through the perforation can be prevented.

FIG. 23 illustrates a cross sectional view similar to FIGS. 21A-21D, 22,wherein a solid substance, such as radioactive seeds 109, has beenplaced in the cavity 103. While in FIG. 23 no basket is shown in thecavity 103, in other embodiments, the cavity 103 may be maintained inits expanded condition by a basket 105, 105A, as described above. Theuse of a basket or other effectors aimed at preserving the inner volumeof the cavity 103 may be beneficial when the cavity 103 has been formedin a soft tissue, or is surrounded by soft tissue. In some embodiments,the cavity 103 may be formed in harder tissue, such as bone tissue orcartilaginous tissue. An effector, such as a basket, aimed atmaintaining the cavity in its expanded condition could then be dispensedwith.

While the invention has been described in terms of various specificembodiments, it will be apparent to those of ordinary skill in the artthat many modifications, changes, and omissions are possible withoutdeparting form the spirit and scope of the claims. In addition, unlessspecified otherwise herein, the order or sequence of any process ormethod steps may be varied or re-sequenced according to alternativeembodiments.

For instance, while the above described exemplary embodiments use lasersources and laser energy to obtain tissue ablation through vaporization,the option is not ruled out of using a different power source, such as aradiofrequency power source, and respective energy delivery device, todeliver the energy in the tissue volumes where ablation is required.

What is claimed is:
 1. A method of treating benign prostatic hyperplasiain a patient in need of said treatment, comprising the following steps:trans-perineally introducing at least one energy delivery device througha perineal area of the patient in a first position in a prostate of thepatient; delivering energy from an energy source through the energydelivery device to a first volume of tissue of said prostate, until saidfirst volume is vaporized or sublimated and a cavity is formed in theprostate tissue; removing the energy delivery device from the prostate;and reducing the volume of the cavity such that compression of theurethra by prostate tissue surrounding the urethra is relieved.
 2. Themethod of claim 1, wherein the energy source comprises a laser source.3. The method of claim 1, further comprising the following steps; (a)pulling back the energy delivery device from the first position to asecond position; (b) delivering energy from the energy source throughthe energy delivery device to a second volume of tissue of said prostatewhile the energy delivery device is in the second position, until saidsecond volume is vaporized or sublimated and the cavity is enlarged; and(c) repeating steps (a) and (b), if needed.
 4. The method of claim 1,further comprising the step of removing vapor or gas resulting from thetissue vaporization or sublimation while energy is delivered through theenergy delivery device.
 5. The method of claim 1, further comprising thestep of removing vapor or gas resulting from the tissue vaporization orsublimation through the energy delivery device.
 6. The method of claim5, wherein the step of removing vapor or gas comprises the step ofapplying a negative pressure through the energy delivery device.
 7. Themethod of claim 5, wherein the step of removing vapor or gas comprisesthe step of circulating a clean fluid medium in the cavity.
 8. Themethod of claim 5, wherein the step of removing vapor or gas comprisesthe step of fluidly coupling a vacuum pump to a pathway of the energydelivery device.
 9. The method of claim 1, further comprising the stepsof: introducing an inflatable balloon in the urethra of the patient;inflating said inflatable balloon; deflating said inflatable balloonafter sublimation or vaporization of the tissue; and removing theinflatable balloon from the urethra.
 10. The method of claim 9, furthercomprising the step of circulating a fluid in the balloon.
 11. Themethod of claim 10, further comprising the step of controlling thetemperature of the fluid circulating in the balloon.
 12. The method ofclaim 9, wherein said balloon has at least one enlarged terminal endadapted to maintain the balloon in position during treatment.
 13. Themethod of claim 1, further comprising the steps of: introducing atrans-rectal imaging probe in the rectum of the patient; and performingthe treatment under imaging control through the trans-rectal imagingprobe.
 14. The method of claim 1, further comprising the steps of:introducing at least one temperature sensing device in the prostate; anddetecting the temperature in at least one location inside the prostateduring energy delivering.
 15. The method of claim 14, further comprisingthe step of controlling the energy source based upon temperatureinformation from the temperature sensing device.
 16. The method of claim14, wherein the step of introducing at least one temperature sensingdevice comprises the step of introducing said temperature sensing devicebetween a volume of action of the energy delivery device and a criticalstructure of the prostate.
 17. The method of claim 16, wherein thecritical structure of the prostate is one of an urethra, a prostatecapsule and neuro-vascular bundles around the prostate.
 18. The methodof claim 14, wherein the temperature sensing device is introducedtrans-perineally in the prostate.
 19. The method of claim 1, furthercomprising the step of performing a trans-rectal massage of the prostateafter formation of said cavity, promoting cavity collapse.
 20. A methodof removing tissue form an organ of a patient, comprising the followingsteps: introducing at least one energy delivery device in a firstposition in an organ of the patient; delivering energy from an energysource through the energy delivery device to a first volume of tissue ofsaid organ, until said first volume is vaporized or sublimated and acavity is formed in the organ tissue; removing the energy deliverydevice from the organ.
 21. The method of claim 20, further including thestep of reducing the volume of the cavity.
 22. The method of claim 20,further including the step of introducing in said cavity at least oneof: a medicament, a drug, a slow-absorption drug, a radioactive seed, achemotherapeutic agent, nanoparticles, a drug carrier, an expandablebasket.